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Articles 1 - 30 of 661

Full-Text Articles in Physics

Analog Implementation Of The Hodgkin-Huxley Model Neuron, Zachary D. Mobille, George H. Rutherford, Jordan Brandt-Trainer, Rosangela Follmann, Epaminondas Rosa Oct 2019

Analog Implementation Of The Hodgkin-Huxley Model Neuron, Zachary D. Mobille, George H. Rutherford, Jordan Brandt-Trainer, Rosangela Follmann, Epaminondas Rosa

Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.


Period Drift In A Neutrally Stable Stochastic Oscillator, Kevin Sanft Oct 2019

Period Drift In A Neutrally Stable Stochastic Oscillator, Kevin Sanft

Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.


Monte Carlo Simulations Of Electrothermal Transport In Nanoelectronics, T. J. Spence Sep 2019

Monte Carlo Simulations Of Electrothermal Transport In Nanoelectronics, T. J. Spence

Science Seminars

The field of microelectronics plays an important role in many areas of engineering and science, being ubiquitous in aerospace, industrial manufacturing, biotechnology, and many other fields. The capacity to simulate new devices accurately is critical to the engineering design process, as device engineers use simulations to predict performance characteristics and identify potential issues before fabrication. In this talk, a Monte Carlo technique is presented for solving the classical Boltzmann Transport Equation, Poisson’s and Schrödinger’s equations for electrons and phonons.


Application Of The Optimal Estimation Method (Oem) To Retrieve Relative Humidity From Raman Lidar Backscatter Measurements., Shayamila N. Mahagammulla Gamage, Robert Sica, Alexander Haefele Jun 2019

Application Of The Optimal Estimation Method (Oem) To Retrieve Relative Humidity From Raman Lidar Backscatter Measurements., Shayamila N. Mahagammulla Gamage, Robert Sica, Alexander Haefele

Western Research Forum

Accurate measurements of relative humidity (RH) vertical profiles in the atmosphere is important for understanding the earth's weather and the climate system. RH represent the current state of the water vapor in the atmosphere with respect to the ambient air related to saturation. Even minor changes of the RH in the lower atmosphere has a large impact of the global circulation and cloud formation. Due to its high variability RH measurements in the lower atmosphere is significantly challenging. Raman lidar is one of the potential tools that can provide vertical profiles of RH. Typically, temperature and water vapor mixing ...


Polychromatic Map Reconstruction Using Telescopes With Asymmetric Antenna Patterns, Connor Mooney, Solomon Quinn, Emory F. Bunn Jun 2019

Polychromatic Map Reconstruction Using Telescopes With Asymmetric Antenna Patterns, Connor Mooney, Solomon Quinn, Emory F. Bunn

Arts & Sciences Student Symposium

Imaging telescopes with asymmetric antenna patterns that vary with wavelength can create time-ordered data that may be processed into multiple images corresponding to different bands of wavelengths from just a single set of scans. The imaging telescope named QUBIC has this property and is the inspiration behind this project. Our goal is to quantify, both statistically and analytically, the ability of these telescopes to perform such a reconstruction given different cases. In the case that the telescope is observing the full sky, we reconstruct our maps via a spherical harmonic basis. In this way, the reconstructed images are described as ...


The Challenge For Vision Of Fluctuating Real-World Illumination, David H. Foster May 2019

The Challenge For Vision Of Fluctuating Real-World Illumination, David H. Foster

MODVIS Workshop

No abstract provided.


Effects Of Wavelength Variation On Localized Photoemission In Triangular Gold Antennas, Christopher M. Scheffler, Robert Campbell Word, Rolf Könenkamp May 2019

Effects Of Wavelength Variation On Localized Photoemission In Triangular Gold Antennas, Christopher M. Scheffler, Robert Campbell Word, Rolf Könenkamp

Student Research Symposium

Exposing metal-dielectric structures to light can result in surface plasmon excitation and propagation along the transition interface, creating a surface plasmon polariton (SPP) response. Photoemission electron microscopy (PEEM) has been used to image nanometer scale plasmonic responses in micron-sized plasmonic devices. With PEEM, optical responses can be characterized in detail, aiding in the development of new types of plasmonic structures and their applications. In thin, triangular gold platelets SPPs can be excited and concentrated within specific regions of the material. In this regard, the platelets act as receiver antennas by converting the incident light into localized excitations in specific regions ...


High Resolution Validation Of Next Generation Turbulent Flow Models Using Neutron Beams, Laser Fluorescence, And Cryogenic Helium, Landen G Mcdonald May 2019

High Resolution Validation Of Next Generation Turbulent Flow Models Using Neutron Beams, Laser Fluorescence, And Cryogenic Helium, Landen G Mcdonald

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

Turbulent fluid flow is an incredibly unpredictable subject that continues to confound scientists and engineers. All of the empirical data that has been the basis of conventional turbulent computational fluid dynamics (CFD) models for decades only extends to roughly the equivalent turbulence created when Michael Phelps swims in a pool. The problem is that this data is then extrapolated out many orders of magnitude in order to design cruise ships, airplanes, and rockets which operate in significantly more turbulent flow regimes. This creates an incredible degree of uncertainty in the design process that demands over-engineering and increased expenditures.

The development ...


Brain Network Structure And Interventions In A Computational Model Of Epilepsy, Joe Emerson Apr 2019

Brain Network Structure And Interventions In A Computational Model Of Epilepsy, Joe Emerson

Student Symposium

Some forms of drug-resistant epilepsy can only be treated via surgical intervention. This form of treatment requires the removal of a part of the brain identified as the seizure source. Current methods for surgical treatment are risky and many times unsuccessful. A deeper understanding of how brain connectivity facilitates seizure propagation is necessary for developing improved surgical techniques. Experimental limitations make certain clinical investigations of epilepsy difficult or impossible, but computational modeling offers a way forward when experimentation in living systems is impractical or unsafe. We used a full-hemisphere computational model for epilepsy to investigate the role of network structure ...


Predicting Chaotic Behavior In Electrical Circuits, Trey Scofield Apr 2019

Predicting Chaotic Behavior In Electrical Circuits, Trey Scofield

Carroll College Student Undergraduate Research Festival

Chaotic behavior is a natural phenomenon that can be found all around us in our daily lives. This project is focused on analyzing the behavior in forced RL-Diode (resistor, inductor, and diode) electrical circuits. We determined that when the sinusoidal input voltage of the circuit was increased, the voltage across the diode experienced period doubling, quadrupling, and then eventually chaos. Furthermore, this project is focused on predicting when and how these chaotic properties emerged from data that we collected. The primary machine learning technique that is used to predict chaos properties is a recurring neural network called an echo state ...


Local Structural Determination In Strained-Layer Semiconductors, Joseph Woicik Apr 2019

Local Structural Determination In Strained-Layer Semiconductors, Joseph Woicik

Sustainability Seminar Series

The theory of elasticity accurately describes the deformations of macroscopic bodies under the action of applied stress. In this lecture I will examine the internal mechanisms of elasticity for strained-layer semiconductor heterostructures. In particular, I will present extended x-ray absorption fine structure (EXAFS) and x-ray diffraction (XRD) measurements to show how bond lengths and bond angles change with strain and compare with various theoretical models. These synchrotron-based experimental techniques and their application to thin films will be developed in detail.


Autonomous Watercraft Simulation And Programming, Nicholas J. Savino Apr 2019

Autonomous Watercraft Simulation And Programming, Nicholas J. Savino

Student Scholar Showcase

Automation of various modes of transportation is thought to make travel more safe and efficient. Over the past several decades, advances to semi-autonomous and autonomous vehicles have led to advanced autopilot systems on planes and boats, and an increasing popularity of self-driving cars. We predicted the motion of an autonomous vehicle using simulations in Python. The simulation models the motion of a small scale watercraft, which can then be built and programmed using an Arduino Microcontroller. We examined different control methods for a simulated rescue craft to reach a target. We also examined the effects of different factors, such as ...


Implementation Of Fast Hydraulic Erosion Simulation And Visualization On Gpu, Brian Hawkins Apr 2019

Implementation Of Fast Hydraulic Erosion Simulation And Visualization On Gpu, Brian Hawkins

Computer Science Graduate Research Workshop

No abstract provided.


First Principles Study Of Surface States And Tetragonal Distortion In Half Metals, Sam Prophet, Rishabh Dalal, Parashu Kharel, Pavel Lukashev Apr 2019

First Principles Study Of Surface States And Tetragonal Distortion In Half Metals, Sam Prophet, Rishabh Dalal, Parashu Kharel, Pavel Lukashev

Research in the Capitol

Magnetic materials have been an increasingly popular area of research over the past decade. Half-metallic materials, in particular, are of specific interest due to their high degree of spin-polarization. One application of these materials that is of interest is spintronics. Electronics utilize the electric charge of electrons, while spintronics utilizes the spin of these electrons instead. Half-metals are very promising for this application, as they generally hold their magnetic properties up to high temperatures, and are relatively cheap compared to other metals. The following research has two goals for two different half metals. Firstly, identify the so called ‘surface properties ...


Second-Harmonic Generation From Hyperbolic Plasmonic Nanorod Metamaterial Slab, Gregory Wurtz Mar 2019

Second-Harmonic Generation From Hyperbolic Plasmonic Nanorod Metamaterial Slab, Gregory Wurtz

Showcase of Faculty Scholarly & Creative Activity

Hyperbolic plasmonic metamaterials provide numerous opportunities for designing unusual linear and nonlinear optical properties. In this work, second-harmonic generation in a hyperbolic metamaterial due to a free-electron nonlinear response of a plasmonic component of the metamaterial is studied. It is shown that owing to a rich modal structure of an anisotropic plasmonic metamaterial slab, the overlap of fundamental and second-harmonic modes results in the broadband enhancement of radiated second-harmonic intensity by up to 2 orders of magnitude for TM- and TE-polarized fundamental light, compared to a smooth Au film under TM-polarised illumination. Compared to the radiated second-harmonic intensity from a ...


Spiral Waves Modeling, Paulo H. Acioli Nov 2018

Spiral Waves Modeling, Paulo H. Acioli

Faculty Research and Creative Activities Symposium

No abstract provided.


Measuring The One-Way Velocity Of Light, Charles Nissim-Sabat Nov 2018

Measuring The One-Way Velocity Of Light, Charles Nissim-Sabat

Faculty Research and Creative Activities Symposium

No abstract provided.


Cementitious Sensors Exhibiting Stopbands In Acoustic Transmission Spectra, Shreya Vemuganti Nov 2018

Cementitious Sensors Exhibiting Stopbands In Acoustic Transmission Spectra, Shreya Vemuganti

Shared Knowledge Conference

Ultrasonic monitoring in cementitious materials is challenging due to the high degree of attenuation. In wellbore environments, monitoring becomes more challenging due to inaccessibility. Meta materials, also known as acoustic bandgap materials, exhibit an interesting feature of forbidding the propagation of elastic/sound waves and isolate vibration in a certain frequency band. Traditionally, acoustic bandgap materials are developed with inclusions such as tin, aluminum, gold, steel in a polymer matrix. In this study, we present the development of three-dimensional cementitious sensors capable of exhibiting stopbands in the acoustic transmission spectra using carbon nanotubes. Relatively wide stopbands were engineered using Floquet-Bloch ...


Nonthermal Dark Matter From Early Matter Domination, Jacek Ksawery Osinski Nov 2018

Nonthermal Dark Matter From Early Matter Domination, Jacek Ksawery Osinski

Shared Knowledge Conference

Dark matter (DM) production in the early universe traditionally assumes a standard thermal history where the universe is in a radiation-dominated phase after the end of inflation until matter-radiation equality. However, the presence of additional scalar fields (which is a generic prediction of explicit string constructions) can lead to an epoch of early matter domination (EMD) that ends before the onset of big bang nucleosynthesis. Such an EMD phase has important cosmological consequences and renders thermal production of DM irrelevant. We present three scenarios for DM production involving an era of EMD: evaporation of primordial black holes into DM, DM ...


Sampling Complexity Of Bosonic Random Walkers On A One-Dimensional Lattice, Gopikrishnan Muraleedharan, Akimasa Miyake, Ivan Deutsch Nov 2018

Sampling Complexity Of Bosonic Random Walkers On A One-Dimensional Lattice, Gopikrishnan Muraleedharan, Akimasa Miyake, Ivan Deutsch

Shared Knowledge Conference

Computers based quantum logic are believed to solve problems faster and more efficiently than computers based on classical boolean logic. However, a large-scale universal quantum computer with error correction may not be realized in near future. But we can ask the question: can we devise a specific problem that a quantum device can solve faster than current state of the art super computers? One such problem is the so called "Boson Sampling" problem introduced by Aaronson and Arkhipov. The problem is to generate random numbers according to same distribution as the output number configurations of photons in linear optics. It ...


Pulsed Fiber Optics Lasers As Highly Sensitive Sensors, Hanieh Afkhamiardakani Nov 2018

Pulsed Fiber Optics Lasers As Highly Sensitive Sensors, Hanieh Afkhamiardakani

Shared Knowledge Conference

An interferometer or resonator is a device in which optical beams of specific frequencies circulate with minimal losses. These losses are completely compensated by the gain inside a laser resonator. A small perturbation introduced inside the laser can affect its frequency, which in turns becomes a metric of that perturbation. The perturbation is usually caused by an electric or magnetic field, rotation, acceleration, nonlinear index of refraction etc. Tiny changes of optical frequency are monitored by superimposing the laser field and a reference field (from the same laser) on a detector. This technique requires creating a laser in which two ...


Two Applications Of High Order Methods: Wave Propagation And Accelerator Physics, Oleksii Beznosov Nov 2018

Two Applications Of High Order Methods: Wave Propagation And Accelerator Physics, Oleksii Beznosov

Shared Knowledge Conference

Numerical simulations of partial differential equations (PDE) are used to predict the behavior of complex physics phenomena when the real life experiments are expensive. Discretization of a PDE is the representation of the continuous problem as a discrete problem that can be solved on a computer. The discretization always introduces a certain inaccuracy caused by the numerical approximation. By increasing the computational cost of the numerical algorithm the solution can be computed more accurately. In the theory of numerical analysis this fact is called the convergence of the numerical algorithm. The idea behind high order methods is to improve the ...


Charge Transfer Plasmon Resonances In Metallic Nanorod-Film Systems, Paul J. Gieri Nov 2018

Charge Transfer Plasmon Resonances In Metallic Nanorod-Film Systems, Paul J. Gieri

Shared Knowledge Conference

Understanding how the plasmonic response of colloidally grown metallic nanostructures changes when coupled to a metallic film is an important research problem with significant consequences for a number of applications such as sensing, solar energy harvesting, spectroscopy, and photochemistry, to name a few. In this work we investigate, both through experimental and theoretical approaches, the optical response of ligand coated gold nanorods and their interaction with gold films. We find that the scattering response of these systems is dominated by a charge transfer plasmon, in which charge flows between the particle and film. Additionally, we show that the characteristics of ...


Genetic Algorithm Design Of Photonic Crystals For Energy-Efficient Ultrafast Laser Transmitters, Troy A. Hutchins-Delgado Nov 2018

Genetic Algorithm Design Of Photonic Crystals For Energy-Efficient Ultrafast Laser Transmitters, Troy A. Hutchins-Delgado

Shared Knowledge Conference

Photonic crystals allow light to be controlled and manipulated such that novel photonic devices can be created. We are interested in using photonic crystals to increase the energy efficiency of our semiconductor whistle-geometry ring lasers. A photonic crystal will enable us to reduce the ring size, while maintaining confinement, thereby reducing its operating power. Photonic crystals can also exhibit slow light that will increase the interaction with the material. This will increase the gain, and therefore, lower the threshold for lasing to occur. Designing a photonic crystal for a particular application can be a challenge due to its number of ...


Combined High-Speed Single Particle Tracking Of Membrane Proteins And Super-Resolution Of Membrane-Associated Structures, Hanieh Mazloom Farsibaf, Keith A. Lidke Nov 2018

Combined High-Speed Single Particle Tracking Of Membrane Proteins And Super-Resolution Of Membrane-Associated Structures, Hanieh Mazloom Farsibaf, Keith A. Lidke

Shared Knowledge Conference

Many experiments have shown that the diffusive motion of lipids and membrane proteins are slower on the cell surface than those in artificial lipid bilayers or blebs. One hypothesis that may partially explain this mystery is the effect of the cytoskeleton structures on the protein dynamics. A model proposed by Kusumi [1] is the Fence-Picket Model which describes the cell membrane as a set of compartment regions, each ~ 10 to 200 nm in size, created by direct or indirect interaction of lipids and proteins with actin filaments just below the membrane. To test this hypothesis, we have assembled a high-speed ...


Plasmon-Enhanced Quadrupolar Transitions With Nanostructured Graphene, Stephen Sanders Nov 2018

Plasmon-Enhanced Quadrupolar Transitions With Nanostructured Graphene, Stephen Sanders

Shared Knowledge Conference

Many important molecules have quadrupolar excitations which occur at much slower rates than the competing dipolar transitions and hence are termed forbidden. In this work, we propose a new approach to enhance quadrupolar transitions using graphene nanostructures. We provide a detailed investigation of the enhanced transition rate in the vicinity of graphene nanoislands and use rigorous computational methods to analyze how this quantity changes with the geometrical and material parameters of the nanoisland. To support these calculations we also provide a semi-analytic approach. Finally, we investigate the performance of arrays of graphene nanoribbons, which constitutes a suitable platform for the ...


Two-Dimensional Layered Materials (Graphene-Mos2) Nanocatalysts For Hydrogen Production, Jacob Dobler, Taylor Robinson, Sanju Gupta 7455940 Nov 2018

Two-Dimensional Layered Materials (Graphene-Mos2) Nanocatalysts For Hydrogen Production, Jacob Dobler, Taylor Robinson, Sanju Gupta 7455940

Posters-at-the-Capitol

Recent development of two-dimensional layered materials including graphene-family and related nanomaterials have arisen as potential game changer for energy, water and sensing applications. While graphene is a form of carbon arranged hexagonally within atomic thin sheet, MoS2 is becoming a popular, efficient, and cost-effective catalyst for electrochemical energy devices, in contrast to expensive platinum and palladium catalysts. In this work, we electrochemically desulfurize few-layer molybdenum disulfide (MoS2) and aerogels with reduced graphene oxide (rGO) prepared under hydrothermal conditions ((P< 20 bar, T< 200 oC), for improving hydrogen evolution reaction (HER) activity via point defects (S-vacancy). Moreover, the interactions between rGO and ...


Physical Properties Of Engineered Nanocomposites For Defense Applications, Alex Henson, Sanju Gupta Nov 2018

Physical Properties Of Engineered Nanocomposites For Defense Applications, Alex Henson, Sanju Gupta

Posters-at-the-Capitol

Polymer nanocomposites are significant for modern and future technologies (aerospace, defense, water purification etc.) due to their tailored properties, lightweight and low cost. However, ‘forward’ engineered polymer (host matrix) composites with smaller size nanoparticles (guest) providing desired properties targeting specific applications remains a challenging task as they depend largely on nanoparticles size, shape and loading (volume fraction). This study develops polymer nanocomposites impregnated with ‘organic-inorganic’ silsesquioxane nanoparticles and graphene nanoribbons, and investigates microscopic structure and dynamics of interfacial layer to predict macroscale properties. The nanocomposites consist of poly(2-vinylpyridine) (P2VP) polymer (segment ~5nm) with spherical silsesquioxane nanoparticles (diameter ~2-5nm) and ...


The Undeniable Attraction Of Lunar Swirls, Cierra Waller, Dhananjay Ravat Nov 2018

The Undeniable Attraction Of Lunar Swirls, Cierra Waller, Dhananjay Ravat

Posters-at-the-Capitol

Lunar swirls are complex patterns on the Moon with distinct brightness signatures and magnetic characteristics. Current research has suggested that the formation of lunar swirls relies on local magnetic fields to shield impinging solar wind, based on a shift in electromagnetic wavelength peaks related to solar radiation and space weathering. Our research combined recent models and methods to characterize these anomalies at the surface of the Moon, exploring the effects of field strength and position. We have produced a high resolution map of a famous swirl named Reiner Gamma using magnetic dipole modeling. These maps and models are considered when ...


9 - Gas Kinetic Model For Argon In A Commercial Plasma System, Zachary Barton Nov 2018

9 - Gas Kinetic Model For Argon In A Commercial Plasma System, Zachary Barton

Georgia Undergraduate Research Conference (GURC)

Gas kinetic models can tell us a lot about how a plasma system operates on the atomic and/or molecular level. Here, we are using a commercial Boltzmann solver to determine the electron energy distribution functions associated with an argon plasma produced by a commercial plasma system. From the EEDF we can gain insight about the electron temperature and electric field inside the device.